In the previous post, we discussed the basics of IP access lists (ACLs) and how to configure standard access lists. In this post, we will explain how to configure an Extended Access List on Cisco routers. If you have any queries regarding the concept of Extended ACL, please visit the following link before start to configure Extended ACL.

An Access Control List (or ACL or simply access list) is a security feature that allows you to filter the network traffic based on configured statements. An ACL can be used to filter either inbound or outbound traffic on an interface. Once you applied an access list on a router, the router examines every packet moving from one interface to another interface in the specified direction and takes the appropriate action. In this post, we will demonstrate the basics of ACL and how to configure Standard ACL on a Cisco router using Cisco Packet Tracer. The same steps can be used to configure Standard ACL in GNS3 or reach Cisco routers.